In recent years, with the rapid development of semiconductor technology, electronic components continuously develop toward minimization, integration and high frequency. Selecting appropriate ceramic material that can be low temperature co-fired with conductive materials such as silver and the like at no more than 900° C., and thus manufacturing multilayer components or plunging a passive component into a multilayer circuit substrate to make functional modules become a necessary requirement for the above trend. Low temperature co-fired ceramic as the major dielectric material of a passive integrated component has also becomes an important developmental trend.
Currently, low temperature co-fired ceramic (LTCC) facilitates densification of the materials mainly by using a liquid phase sintering mechanism after introducing an appropriate amount of sintering aids (low melting point oxide or low melting point glass) into the dielectric ceramic systems.
For example, adding ZnO—B2O3—SiO2 glass, etc. into a BaO—TiO2—WO3 system can decrease a sintering temperature to 1000° C. (JP10294020-A), and adding SiO2—B2O3 system glasses into a CaZrO3—SrTiO3 system can reduce the sintering temperature by 1000° C. However, the ability of the sintering aids to decrease the sintering temperature is limited, and excessive amount of sintering aids would also affect the performance of a device, such as increasing dielectric loss and the like. To obtain electronic ceramic materials with lower sintering temperature and easily controlled dielectric performance, the attention is focused on a ceramic material system in which the low temperature co-firing can be easily achieved, such as a Bi—Zn—Nb—O system (FR2845685-A1), Zr—Ti—Zn—O system (US2003116891-A1, US6762142-B2), ZnNb2O6 and ZnTa2O6 solid solution or MgNb2O6 and MgTa2O6 (US5756412-A, KR98001965A; KR99008479-A; KR203515-B1), Zn—Nb—O system (JP7169330-A), ZnTiO3 (CN1773631, WO2005085154-A1), (Ba1-xSrx)4LiNb3-yTayO12 (CN1793004), BaNd2+xTi5O14+1.5x (CN1634800), Ba—Ti—Ge—Si (JP2000239061-A), Li2+xNb3xTi1-4xO3 (CN1821171 and CN1915904), Zn(1-x)Nb2O6-xTiO2 (KR29499/98), Bi(Nb1-xVx)O4 (CN1793035), Bi3XZn2(1-x)Nb2-xO7 (CN1089247, CN1107128), (Bi3xZn2-3x)(Znx-y/3Nb2-x-2y/3May)O7 and (Bi3xZn2-3x)(ZnxNb2-x-yMby)O7, wherein Ma=Sn4+, Zr4+, Mb=Sb5+, Ta5+, Mo5+(CN1431166), (Bi3xM2-3x)(ZnxNb2-x)O7, wherein, M is Zn2+, Ca2+, or Cd2+, or Sr2+ (CN1792999) and the like. The sintering temperatures of these material systems themselves are low, generally between 950 and 1150° C. The low temperature sintering at about 900° C. can be achieved by mixing in a small amount of glass or low melting point oxide (such as Bi2O3, ZnO, CuO, V2O5 and the like).
However, introducing a low melting point regulator may cause a series of problems, such as reduced mechanical strength of the material after being sintered, or higher dielectric loss as well as complexity of the process. Therefore, it is very necessary to develop low temperature co-fired ceramic having simple components.